Is my EBCM fault the source of other electrical issues?
08-02-2016, 10:46 PM
#1
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Is my EBCM fault the source of other electrical issues?
I've got a few issues I'm seeing on my '01, and I'm wondering if anyone would be able to tell if they seem related to the root cause. These are the symptoms that I'm seeing:
1) Headlights intermittently don't come up. There's no grinding or apparent mechanical reason why they don't come up -- but I just twist the **** and then both headlights will either pop up, or not. It'll work well for a while, then it'll stop working for a while -- all over the span of, say, 20 min.
2) The turn signal will sometimes not blink. If I'm sitting at a traffic light with my left signal on... it'll blink, and then it might just all of a sudden stop blinking and stay off. Turning the signal on and off doesn't have an immediate impact; the signal seems to just work for a while, then not work for a while, as it sees fit.
3) ABS/Traction Control/Active Handling lights illuminate on the dash... though, most of the time. Sometimes the lights and warnings will go away.
I took the car to the dealer, and they identified a C1214 fault and told me that I need to replace both the EBCM and the BPMV, for a total of ~$4k for parts and labor. I'm trying to figure out if its worthwhile replacing them myself, but I'm not certain as to whether it's really bad. There's clearly some electrical issue going on here, but I'd be interested in some thoughts as to whether I'm looking at:
1) an EBCM that's really faulty, but sometimes isn't faulty. Headlights and turn signals are a separate issue.
2) an EBCM that's really faulty, and is causing the other electrical issues
or 3) a perfectly fine EBCM that's reporting a fault due to intermittent electrical issues elsewhere.
I'd appreciate any thoughts you might have. Thanks!!
1) Headlights intermittently don't come up. There's no grinding or apparent mechanical reason why they don't come up -- but I just twist the **** and then both headlights will either pop up, or not. It'll work well for a while, then it'll stop working for a while -- all over the span of, say, 20 min.
2) The turn signal will sometimes not blink. If I'm sitting at a traffic light with my left signal on... it'll blink, and then it might just all of a sudden stop blinking and stay off. Turning the signal on and off doesn't have an immediate impact; the signal seems to just work for a while, then not work for a while, as it sees fit.
3) ABS/Traction Control/Active Handling lights illuminate on the dash... though, most of the time. Sometimes the lights and warnings will go away.
I took the car to the dealer, and they identified a C1214 fault and told me that I need to replace both the EBCM and the BPMV, for a total of ~$4k for parts and labor. I'm trying to figure out if its worthwhile replacing them myself, but I'm not certain as to whether it's really bad. There's clearly some electrical issue going on here, but I'd be interested in some thoughts as to whether I'm looking at:
1) an EBCM that's really faulty, but sometimes isn't faulty. Headlights and turn signals are a separate issue.
2) an EBCM that's really faulty, and is causing the other electrical issues
or 3) a perfectly fine EBCM that's reporting a fault due to intermittent electrical issues elsewhere.
I'd appreciate any thoughts you might have. Thanks!!
Last edited by rrao1217; 08-02-2016 at 10:47 PM.
08-02-2016, 11:08 PM
#2
Safety Car
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St. Jude Donor '14-'15-'16-'17-'18-'19-'20-'21-'22-'23
"3) ABS/Traction Control/Active Handling lights illuminate on the dash... though, most of the time. Sometimes the lights and warnings will go away." Absfixer can fix that.
08-03-2016, 12:04 AM
#4
Melting Slicks
100%. For your AH/TC/ABS light issue pull and post ALL your codes including the H or C or HC that follow each 5 character code. List the codes under the sensors that the codes show under. ie 10- PCM or 28 - TCS or 40 - BCM.....etc.If you have never pulled codes on your car before, here is how:
https://www.youtube.com/watch?v=SviRjIsy9G4
OR
http://www.c5forum.com/ayc/dtcdic.php
On your problem #2 the hazard flasher switch, which has the electronics for the turn signal flasher in it as well, is a well known weak point on the C5 and commonly causes the turn signals to NOT flash. Next time they fail to flash, rapidly operate the hazard switch about a dozen time and see if the turn signals return to working for a short time. Here is a link to the 4 options you have for the hazard switch/turn signal issue:
https://www.corvetteforum.com/forums...post1589443564
Your headlight not opening MAY be the result of worn or missing bump stops that cause the lights to stop on both open and close. The Head Light Control (HLC) module operates the headlight motors and senses higher than normal current as the way it determines to turn off power to the motors. The higher current occurs when the motors run up against the bump stops. If the bump stops are missing or dented heavily from use they may allow the motors to place excess force on the gears that drive the headlight lids on the close operation. This could result in the HLC module sensing high current attempting to open the lids and hence turn off power to the motors thinking the have come against the open stops. Here is a link to a thread that has pictures of the 4 bump stops per motor:
https://www.corvetteforum.com/forums...ght-shake.html
Examine the bump stops for heavy dents in the plastic and try turning the stops 180 degrees if they are dented. You can also purchase new bump stops here:
http://rodneydickman.com/catalog/ind...a50b92464424b4
5th item in the list.
08-03-2016, 01:15 AM
#5
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100%. For your AH/TC/ABS light issue pull and post ALL your codes including the H or C or HC that follow each 5 character code. List the codes under the sensors that the codes show under. ie 10- PCM or 28 - TCS or 40 - BCM.....etc.If you have never pulled codes on your car before, here is how:
https://www.youtube.com/watch?v=SviRjIsy9G4
OR
http://www.c5forum.com/ayc/dtcdic.php
On your problem #2 the hazard flasher switch, which has the electronics for the turn signal flasher in it as well, is a well known weak point on the C5 and commonly causes the turn signals to NOT flash. Next time they fail to flash, rapidly operate the hazard switch about a dozen time and see if the turn signals return to working for a short time. Here is a link to the 4 options you have for the hazard switch/turn signal issue:
https://www.corvetteforum.com/forums...post1589443564
Your headlight not opening MAY be the result of worn or missing bump stops that cause the lights to stop on both open and close. The Head Light Control (HLC) module operates the headlight motors and senses higher than normal current as the way it determines to turn off power to the motors. The higher current occurs when the motors run up against the bump stops. If the bump stops are missing or dented heavily from use they may allow the motors to place excess force on the gears that drive the headlight lids on the close operation. This could result in the HLC module sensing high current attempting to open the lids and hence turn off power to the motors thinking the have come against the open stops. Here is a link to a thread that has pictures of the 4 bump stops per motor:
https://www.corvetteforum.com/forums...ght-shake.html
Examine the bump stops for heavy dents in the plastic and try turning the stops 180 degrees if they are dented. You can also purchase new bump stops here:
http://rodneydickman.com/catalog/ind...a50b92464424b4
5th item in the list.
PCM:
P1431HC
TCS:
C1214HC
LDCM:
B2282H
B2284H
U1064H
RDCM:
B2203H
B2205H
B2283H
B2285H
U1064H
RFA:
U1000H
U1255H
U1064H
The P1431 is another issue I'm having, but so far it's just a minor irritant since my fuel level shows low that I can work on after I work out these issues.
With respect to the HLC and the bump stops -- if that were the case, should I see the headlights get stuck open as well? So far, I've only seen it occur when closed. Though, I'll definitely open that up and check it out.
From what you've said, for now, it sounds like these are indeed 3 distinct issues. If the ABS/TC/AH faults go away intermittently, is it possible there's another cause of the fault than the EBCM, or it is possible that EBCM faults can appear intermittent?
Thanks!!
Last edited by rrao1217; 08-03-2016 at 01:16 AM.
08-03-2016, 11:11 AM
#6
Heel & Toe
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I believe that you definitely have multiple unrelated problems. Perhaps more.
The C1214 can be caused by a number of things including a bad or carboned up ignition switch or even a bad ground for the EBCM. It can also be a cold solder joint in the EBCM. The code relates to the main power relay in the EBCM. Any of those causes can change when the car is driven over a bumpy road. You can start out by checking the grounds related to the EBCM. Here are 2 links related to grounds that you can start with:
http://forums.corvetteforum.com/c5-t...locations.html
http://forums.corvetteforum.com/c5-t...tion-long.html Post #1
The P1431 is also a common fuel system related code. Typically the fuel sensors (there are 2, one in each tank) get a buildup of corrosion on them from hi-sulpher fuels. You can start treating that problem easily. Let the fuel level get to 1/3 tank or less. Add a large bottle(20 Oz) of techron plus to the tank and then fill the tank with your favorite prem. fuel. If possible let the car sit a few days to let the fuel and cleaner solution work on the sensors. Sometimes it will take several treatments to get rid of the problem and then preventative treatment about once a year.
The LDCM and RDCM codes are commonly seen when the battery has gone low or has been disconnected/reconnected.
Don't worry about the RFA codes for now.
My suggestion is to clear ALL the codes (see the video for how to do that) then take the car for a nice drive and when you return pull the codes again BEFORE you shut off the engine. To pull codes with the engine running you must use the reset button to clear any messages displayed in the DIC. Then pull codes as before.
Codes that have returned are the ones that need attention/resolution.
Post what codes do come back.
The C1214 can be caused by a number of things including a bad or carboned up ignition switch or even a bad ground for the EBCM. It can also be a cold solder joint in the EBCM. The code relates to the main power relay in the EBCM. Any of those causes can change when the car is driven over a bumpy road. You can start out by checking the grounds related to the EBCM. Here are 2 links related to grounds that you can start with:
http://forums.corvetteforum.com/c5-t...locations.html
http://forums.corvetteforum.com/c5-t...tion-long.html Post #1
The P1431 is also a common fuel system related code. Typically the fuel sensors (there are 2, one in each tank) get a buildup of corrosion on them from hi-sulpher fuels. You can start treating that problem easily. Let the fuel level get to 1/3 tank or less. Add a large bottle(20 Oz) of techron plus to the tank and then fill the tank with your favorite prem. fuel. If possible let the car sit a few days to let the fuel and cleaner solution work on the sensors. Sometimes it will take several treatments to get rid of the problem and then preventative treatment about once a year.
The LDCM and RDCM codes are commonly seen when the battery has gone low or has been disconnected/reconnected.
Don't worry about the RFA codes for now.
My suggestion is to clear ALL the codes (see the video for how to do that) then take the car for a nice drive and when you return pull the codes again BEFORE you shut off the engine. To pull codes with the engine running you must use the reset button to clear any messages displayed in the DIC. Then pull codes as before.
Codes that have returned are the ones that need attention/resolution.
Post what codes do come back.
It sounds like my next step would be to check out the EBCM for real? Is there something I should be looking for before I pull it out?
Thanks!!
08-03-2016, 01:06 PM
#7
Race Director
I used the thread 8vette7 listed for fixing the 1214. Hardest part was getting the case apart. I would recommend find a long torx driver to get it out, t15 i think is the size. My soldering wasn't the prettiest but it for the job done and no codes for a few weeks now.